1. Field of the Invention
The present invention relates to a fluid bearing apparatus, and more particularly to a fluid bearing apparatus having an increased contacting area of a bearing and rotating elements and a compact size.
2. Description of the Related Art
Recently, with improvements in the fields of information and computer technology, a computer, an audio system, and an image device have been compact in size, thereby there has arisen a need for parts of the computer, the audio system, and the image device to have high accuracy.
In driving motors for various machines, such as a spindle motor for a hard disk drive in the field of auxiliary memory devices and a scanning motor for a laser printer in the field of computer technologies, a driving apparatus for driving a laser disk and a compact disk in the audio system, and a head driving motor of a video cassette recorder and a camcorder, commonly rotate a rotary shaft mounted in the driving motors with high velocity so that readers and recorders of the hard disk drive, the laser printer, the audio system, the video cassette recorder, and the camcorder carry out recording and reproducing of data.
The rotary shaft rotates at very high velocity while creating an oscillation and a vibration. Thereby, the computer, the laser printer, the audio system, the video cassette recorder, the camcorder, and the like using the rotary shaft may have a critical defect.
Accordingly, bearings, as a mechanic element, are used for overcoming problems generated by the high velocity rotation of the rotary shaft of driving motors. There are different kinds of bearings, but a fluid bearing apparatus preferably is used for the rotary shaft rotating at high velocity.
The fluid bearing apparatus generally has dynamic pressure generating grooves formed therein at a predetermined depth. There are two types of the dynamic pressure generating grooves. One type of the dynamic pressure generating grooves is a spiral shape and the other type of the dynamic pressure generating grooves is a herringbone shape.
The dynamic pressure generating grooves having a herringbone shape rotate themselves or the shaft supported by the dynamic pressure generating grooves rotates while the fluids are introduced into the dynamic pressure generating grooves so as to create the vortex flows. The fluids flow through the fluid inlets toward a bending portion and are collected at the bending portion so as to generate a relatively higher pressure.
Also, the spiral type of the dynamic pressure generating grooves may be formed on a surface of the bearing in order to support a thrust load of the rotary shaft.
The herringbone type of the dynamic pressure generating grooves according to the conventional art, support the thrust load of the rotary shaft, however, edges of side walls of the dynamic pressure generating grooves are sharply cut. Thus, not enough fluids are introduced into the dynamic pressure generating grooves to generate the fluids pressure required to shift the rotary shaft in a short time. As a result, there is a problem in that as the length of time required to shift the rotary shaft increases, a friction is generated between the rotary shaft and the thrust bearing and an overload is charged to the rotary shaft and an abrasion of the bearing and a consumption of electric power increases.